drop the hyperhive send/recv/ack_until tools: agents message over matrix

docs/5-project/process/conventions.md

@@ -123,8 +123,7 @@ request still carries an optional `wait_seconds` (long-poll the first
 message, once one arrives — or one is already pending — the call
 drains up to `max` in total): the harness's own turn-driving loop
 uses it internally (`hive-agent`'s `recv_next`, 180s). The
-agent-facing MCP `recv` tool doesn't expose this parameter — it
-always passes `wait_seconds: None`, an immediate peek.
+agent-facing MCP surface has no `recv` tool at all.
 
 Per-row bookkeeping inside the broker:
 
@@ -188,8 +187,8 @@ Per-variant fields:
   3339 on the wire, see *Timestamps on the wire* below); clients
   compute time-until-fire against it.
 - `PendingMessages { count }` — undelivered inbox messages the
-  agent still owes itself a `recv` for. Informational + not
-  cancellable (drain with `recv`); only emitted when `count > 0`,
+  agent has not handled yet. Informational + not
+  cancellable; only emitted when `count > 0`,
   and surfaced first in the list as the most
   actionable signal. Counted host-side from the broker
   (`count_pending`), so it reflects what's genuinely still queued —
@@ -283,7 +282,7 @@ host access it has.
 
 | Permission | Grants |
 |---|---|
-| `messaging` | `send`, `recv`, `ack_until` |
+| `messaging` | nothing (kept as an accepted value; agents message over matrix) |
 | `meta` | `get_agent_meta` (`set_status` is always-on, see below) |
 | `inbox` | `get_loose_ends`, `cancel_loose_end`, `remind` |
 | `execution` | the `bash` MCP server (`mcp__bash__run`/`status`/`kill`), rendered into the agent's MCP config only with it; a subagent gets Claude's own `Bash` instead. See `docs/4-implementation/agent-tools/bash.md`. |